While drilling holes is a common carpentry task that can often be achieved quickly and easily, things become a little more complicated when it comes to milling harder materials like cast iron and steel. When used for these tougher jobs, drill bits have a tendency to deflect off of hard materials and miss their marks. This is what makes the use of spot drills so important, especially when you are drilling into hard materials at high speeds.

Drill Bit Length
One of the biggest factors that leads to issues with drilling operations is the length of the drill bit being used. The longer the tool, the more of a wobble it will have at high speeds. All tools oscillate somewhat when they rotate, though these vibrations are usually too small for us to see with the naked eye. These small vibrations can have big repercussions, because the bit will have a harder time finding purchase in the desired center point. Using shorter drill bits can alleviate this problem, but there is no guarantee that a shorter drill bit won’t deflect.

Spotting
The best way to produce accurate results when drilling into a hard surface is to spot the drill site ahead of time. Spot drills have drill bits that have a very small cutting surface. Typically just the point of the cutter is fluted to make cuts. Instead of being designed to drill holes like other drill bits, these tools are designed to perform a process known as spotting. Spotting is the use of spot drills to create small dimples on the surface of a workpiece to mark the location of holes. Because these tools are so short, they can produce extremely accurate spot points. These points will later help longer twist bits create holes with significantly lower risk of deflecting off the surface of a workpiece.

Choosing the Right Spot Drill
Spotting is a simple process that can offer incredible results, but there are a few important considerations to make sure that your drilling will go as smoothly as possible. Even if a hole location has been properly spotted, the tip of your longer drill bit can contact the side of the spotted location instead of seating properly in the bottom of the spotted point. In order to achieve this, the point angle of your spot drill should be greater than or equal to the point angle of your final drill bit.

If you have been having trouble producing accurate holes while milling, then adding spot drills to your routine could be a great way to get the results that you are looking for. You can find a wide range of high quality drill bits and end mills when you visit www.onlinecarbide.com. Online Carbide is an American tool manufacturer that makes all of their tools from sturdy tungsten carbide tool stock. If you have any questions about any of the tools they carry, feel free to reach out to a member of their team by sending an email to [email protected].